1. Field of the invention:
This invention relates in general to subsea well equipment, and in particular to an apparatus for tying back a wellhead housing located at the sea floor to the surface.
2. Description of the Prior Art:
One type of subsea well employs a wellhead housing located at the sea floor, and a production Christmas tree located at the surface on a platform. Large diameter casing will be lowered from the surface down toward the wellhead housing. A tieback connector will connect the wellhead housing to the riser.
One type of tieback connector has a downward facing funnel that slides over the wellhead housing. The tieback connector has a body with an internal connector device. The connector device will connect to grooves or threads formed in the wellhead housing. Normally, the connection is handled by lowering a running tool and rotating portions of the connector device to move it to a locked position.
While successful, improvements are desired for tieback connectors and running tools wherein large bending forces may be exerted, such as with tension leg platforms.